FRIDAY, Sept. 26, 2025 (HealthDay News) -- Hyperemesis gravidarum is associated with an increased risk for poorer mental health outcomes compared with pregnancy without hyperemesis gravidarum, according to a study published online Sept. 18 in The Lancet Obstetrics, Gynaecology, & Women's Health.Hamilton Morrin, M.B.B.S., from King's College London, and colleagues conducted a retrospective cohort study of anonymized electronic medical records to examine the relative risks for incident neuropsychiatric and mental health outcomes during the first year following a hyperemesis gravidarum diagnosis. A total of 476,857 pregnant women in the TriNetX database were diagnosed with hyperemesis gravidarum across 135 health care providers in 18 high-income and middle-income countries; they were matched with a control cohort of women with pregnancy coding without hyperemesis gravidarum.The researchers found significant relative risks for 18 of 24 outcomes, with the five greatest relative risks for Wernicke encephalopathy, refeeding syndrome, postpartum depression, eating disorders, and antipsychotic prescription (2.39, 2.57, 2.70, 2.06, and 2.23, respectively). There was a reduction in the risk for termination of pregnancy (0.77). For nonaffective psychoses, bipolar affective disorder, intentional self-harm, and suicide attempt, no association was observed."[Hyperemesis gravidarum] can be associated with severe psychiatric disorders that require urgent recognition and joined-up physical and mental health care from the very start of pregnancy," senior author Thomas A. Pollak, Ph.D., also from King's College London, said in a statement.Abstract/Full Text.Sign up for our weekly HealthDay newsletter